Not Applicable
1. Field of the Invention
The present invention relates to a golf club head. More specifically, the present invention relates to a golf club head composed of a composite material.
2. Description of the Related Art
In recent years, substantial attention has been directed toward the development of golf club heads having desired weight characteristics and, in particular, toward the development of golf club heads having a desired center of gravity location. For example, a designer may want to locate the center of gravity of a golf club head in a predetermined or preferred position relative to the face or xe2x80x9csweet spotxe2x80x9d of the golf club head so as to make the golf club head more forgiving upon the occurrence of off-center hits.
Because conventional golf club heads are typically made from metal alloys or other materials having a substantially homogeneous density, the weight characteristics of such golf club heads are typically defined by their overall shape. Thus, to alter the location of the center of gravity of a golf club head, it is often necessary to redesign the shape or configuration of the golf club head. However, this may adversely impact other desired characteristics of the golf club head.
The design process may be further complicated where golf club heads are manufactured using composite materials. Because composite materials are typically less dense than metal and other conventional materials, composite golf club heads generally require additional weighting to achieve desired swing weights for finished golf clubs.
The Rules of Golf, established and interpreted by the United States Golf Association (xe2x80x9cUSGAxe2x80x9d) and The Royal and Ancient Golf Club of Saint Andrews, set forth certain requirements for a golf club head. The requirements for a golf club head are found in Rule 4 and Appendix II. A complete description of the Rules of Golf are available on the USGA web page at www.usga.org. Although the Rules of Golf do not expressly state specific parameters for a golf club, Rule 4-1d states that the club head shall be generally plain in shape, and all parts shall be rigid, structural in nature and functional.
Many solutions have been proposed to adjust and/or increase the weight of composite golf club heads. For example, a weighting agent or material is often introduced into a cavity within a golf club head subsequent to manufacture. In the case of wood type golf club heads, the cavity may be enclosed by the face, sides, sole and crown of the golf club head. However, it is not uncommon for cavities also to be formed, for example, in the sole, heel or toe regions of iron or putter type golf club heads. Because of limited access to the cavities, however, such weighting materials may not be placed as precisely as desired and may not provide the ability to adjust the weight of the golf club heads, or the location of the center of gravity of the golf club heads, very precisely. Furthermore, such materials may dry and separate from the walls of the golf club heads during use, adversely affecting the weight of the golf club heads and possibly creating a distracting sound or feel when the golf clubs are swung.
Alternatively, a composite golf club head may be provided with a metal sole plate or, in the case of wood type golf club heads, a solid or foam core. However, the use of metal sole plates may add undesirable steps in the process of making the golf club heads, and the use of solid or foam core materials has been shown generally to be ineffective for adjusting the location of the center of gravity and moments of inertia of golf club heads. The reason for this is that solid or foam core materials generally have a uniform density, making it difficult to adjust the location of the center of gravity or moments of inertia of the golf club head without simultaneously altering the shape or configuration of the golf club head. Additionally, such materials may result in voids within the golf club head.
For a golf club head including composite material, higher density layers of composite fiber may be provided in the wall of the golf club head to increase its weight. However, such changes in the layers of composite material may affect the structural characteristics of the golf club head.
In view of the foregoing, there appears to be a substantial need for improved methods of manufacturing composite golf club heads and, in particular, for methods that allow for more effective adjustment of the weight characteristics of golf club heads without substantially affecting the structural characteristics of the golf club heads.
The present invention provides a solution for adding mass to a relatively lightweight composite body of a golf club head. This unique and novel solution allows for manipulation of the center of gravity and moments of inertia of the golf club head in order to provide a golf club head that is better performing and more forgiving than similar golf club heads of the prior art.
One aspect of the present invention is a golf club head having a composite body and a plurality of weight members. The body has a hollow interior and is composed of a plurality of plies of pre-preg material. The body has a striking plate, a crown and a sole with a bottom portion and a ribbon. The body has a volume ranging from 200 cubic centimeters to 450 cubic centimeters and a mass ranging from 80 grams to 120 grams. The plurality of weight members are embedded between the plurality of plies of pre-preg material in the ribbon. Each of the plurality of weight members is composed of a polymer material integrated with a metal material. Each of the plurality of weight members has a density ranging from 5 grams per cubic centimeter to 20 grams per cubic centimeter. The plurality of weight members have a combined mass ranging from 40 grams to 70 grams. The golf club head has a mass ranging from 170 grams to 250 grams.
Another aspect of the present invention is a golf club head that has a moment of inertia ranging from 2500 grams-centimeter squared to 3500 grams-centimeter squared about the Izz axis through the center of gravity. The golf club head has a body and a plurality of weight members. The body has a hollow interior and is composed of a plurality of layers of plies of pre-preg material. The body has a striking plate, a crown and a sole with a bottom portion and a ribbon with an upper wall and a lower wall. The body has a volume ranging from 300 cubic centimeters to 400 cubic centimeters and a mass ranging from 90 grams to 115 grams. The plurality of weight members are embedded between the plurality of plies of pre-preg material in the upper wall of the ribbon. Each of the plurality of weight members is composed of a polyurethane material integrated with tungsten. Each of the plurality of weight members has a density ranging from 5 grams per cubic centimeter to 10 grams per cubic centimeter. The plurality of weight members have a combined mass ranging from 40 grams to 60 grams, and the golf club head has a mass ranging from 170 grams to 220 grams.